(a) Field of the Invention
The present invention relates to a pneumatic hybrid electric engine (PHEE) and, more particularly, to a PHEE that is a combination of a pneumatic engine and an electric motor engine, which can fully obtain initial start power by timely switching the power source from the pneumatic engine to the electric motor engine or vice versa according to the variation of the engine load.
(b) Description of the Related Art
Generally, an engine is a device for generating power that can be used for operating vehicles or ships. As the industry develops, a variety of engines have been proposed.
In the initial stages of the industrial revolution, steam engines had usually been used. However, since the steam locomotives or steam ships using such a steam engine use a coal for fuel, the energy efficiency is very low while emitting noxious fumes.
To solve the above problems, combustion engines using gasoline or diesel oil for fuel has been developed to improve the combustion efficiency and solve the problem of the air pollution. Such a combustion engine has been used for vehicle up-to-now.
However, in recent years, as the environment regulation has been increasingly tightened, a power generation system that can alleviate the air pollution has been required to replace the combustion engine. Accordingly, an engine using nonpolluting fuel such as electric energy has been briskly developed.
However, a vehicle provided with the engine using electricity has a problem in being commercialized due to the following reasons.
That is, the vehicle requires a large capacity of start power during the initial engine start. Accordingly, in the electric engine, the excessive current should be supplied to the motor during the initial engine start, resulting in the reduction of the life of the motor. In addition, when the vehicle runs an uphill for a long time, the excessive current is also supplied to the motor. This also causes the life of the motor to be reduced.